Lexq Cli MCP Server

LexQ CLI

The Decision Operations Platform for engineering teams. CLI and MCP server for LexQ. Move business rules out of your deploy pipeline, prove every change with Impact Simulation, and ship without a git push.

Website · Docs · Console · MCP Registry

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Why LexQ?

Your business rules, such as pricing, promotions, fee logic, and eligibility checks, change often. But every change ships through the same PR → review → staging → deploy cycle as your core application code, so even a small change waits for the next release.

LexQ keeps those rules out of your code. Your service calls the LexQ API to evaluate them. You change rules in a visual console or through this CLI, test each change with Impact Simulation against past executions or a dataset you upload, and deploy them without an application release.

Every decision leaves a full audit trail.

Install

npm install -g @lexq/cli

Or run without installing:

npx @lexq/cli

Requires Node.js 22+.

Quick Start

# 1. Authenticate
lexq auth login
# Enter your API key (create one with the Manage scope at console.lexq.io → Management → API Keys)

# 2. Verify
lexq auth whoami

# 3. Start from a domain template — provisions facts, sample rules, and a policy group
lexq domain-templates list
lexq domain-templates apply --template ECOMMERCE
# Returns: policyGroupId, policyVersionId, factsCreated, rulesCreated

# 4. Test a rule against your data before shipping
lexq analytics dry-run --version-id <VERSION_ID> --debug \
  --json '{"facts":{"loyaltyTier":"PLATINUM","purchaseSubtotalUsd":150}}'

# 5. Deploy
lexq deploy publish --group-id <GROUP_ID> --version-id <VERSION_ID> --memo "v1"
lexq deploy live --group-id <GROUP_ID> --version-id <VERSION_ID> --memo "Initial deploy"

For AI Agents

Claude, Cursor, and other MCP-compatible agents can use the Model Context Protocol to manage policy groups, versions, rules, and facts, run simulations and replays, deploy versions, and read execution history.

Approval happens in your MCP client, which decides which tool calls you confirm. The deploy, rollback, and undeploy tools are marked as destructive, so a client can ask you before running them.

Claude.ai (cloud, no install)

1. Customize → Connectors → + Add → Add custom connector
2. Name it, enter https://mcp.lexq.io, and choose Sign in now
3. On the LexQ page that opens, sign in and generate a new API key for MCP, or choose I already have an API key and paste an existing one
4. The tools are now available in every conversation

Remote (Streamable HTTP)

For any MCP client that supports remote servers:

{
  "mcpServers": {
    "lexq": {
      "url": "https://mcp.lexq.io"
    }
  }
}

OAuth 2.1 authentication is handled automatically by your client.

Local (stdio)

Run LexQ CLI as a local MCP server:

lexq serve --mcp

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "lexq": {
      "command": "npx",
      "args": [
        "-y",
        "@lexq/cli",
        "serve",
        "--mcp"
      ]
    }
  }
}

VS Code / Cursor

.vscode/mcp.json:

{
  "servers": {
    "lexq": {
      "command": "npx",
      "args": [
        "-y",
        "@lexq/cli",
        "serve",
        "--mcp"
      ]
    }
  }
}

Prerequisite: lexq auth login must have been run once to store an API key in ~/.lexq/config.json, or LEXQ_API_KEY must be set in the client's environment block.

Registry

The server is listed on the official MCP Registry as io.lexq/lexq. Clients that browse the registry find both the npm package and the hosted endpoint in that one entry.

Protocol Support

The local stdio server and the hosted Streamable HTTP endpoint both serve two MCP revisions from one set of tool definitions, so a client sees the same tools either way.

There is nothing to configure. The server answers in whichever revision the opening message used, so a client can move to 2026-07-28 on its own schedule and one that has not moved keeps working.

AI Agent Skills

LexQ CLI ships with AI Agent Skills: structured documentation that tells agents how to use each tool.

skills/
├── lexq-shared/SKILL.md       Core concepts, auth, workflow
├── lexq-groups/SKILL.md       Policy groups, conflict resolution, A/B testing
├── lexq-rules/SKILL.md        Condition syntax, action types, mutex
├── lexq-simulation/SKILL.md   Dry run, Impact Simulation, compare
├── lexq-execution/SKILL.md    History, stats, failure logs, provenance, replay, latency profile
└── lexq-recipes/SKILL.md      End-to-end recipes

.claude/CLAUDE.md              Claude Code project context
AGENTS.md                      Universal agent guide (Cursor, Windsurf, Gemini CLI, Cline)
CONTEXT.md                     Platform architecture & glossary

After installing @lexq/cli, agents can read skills from:

node_modules/@lexq/cli/skills/
node_modules/@lexq/cli/AGENTS.md
node_modules/@lexq/cli/CONTEXT.md

Commands

lexq auth                  login | logout | whoami
lexq status                API health check
lexq serve                 Run as MCP stdio server (--mcp)
lexq groups                list | get | create | update | delete | reorder
lexq groups ab-test        start | stop | adjust
lexq versions              list | get | create | update | delete | clone
lexq rules                 list | get | create | update | delete | reorder | toggle
lexq facts                 list | create | update | delete | action-metadata | unregistered
lexq domain-templates      list | preview | apply
lexq deploy                publish | live | rollback | undeploy | history | detail | overview | deployable | diff | schedule | unschedule | schedules
lexq analytics             dry-run | dry-run-compare | requirements
lexq analytics simulation  start | status | list | cancel | export
lexq analytics dataset     upload | template
lexq profile               <groupId> — per-rule latency profile
lexq history               list | get | stats
lexq replay                decision | start | list | get | cancel
lexq logs                  list | get | action | bulk-action
lexq provenance            get | reveal-audits
lexq webhook-subscriptions list | get | save | delete | test

Global Options

Configuration

Config is stored at ~/.lexq/config.json:

{
  "apiKey": "YOUR_API_KEY",
  "baseUrl": "https://api.lexq.io/api/v1/partners",
  "format": "json"
}

The file holds an API key in plain text. It is saved with mode 0600 inside a 0700 directory, so only its owner can read it. If an older version created it with looser permissions, the CLI tightens them the next time it saves the file.

Environment variables

These are read by the MCP server (lexq serve --mcp) and take precedence over the stored config. They let an editor or CI target an environment through the client's own config block, without writing to ~/.lexq/config.json. CLI commands use --api-key and --base-url instead.

Development

git clone https://github.com/lexq-io/lexq-cli.git
cd lexq-cli
pnpm install
pnpm build
pnpm start -- groups list

pnpm typecheck                  # Type check
pnpm lint                       # ESLint
pnpm build                      # Bundle to dist/

Checks that guard a stated fact against the thing that owns it. All of them run in CI.

pnpm enums:check                # Generated enums match the engine contract
pnpm prose:check                # Numbers and code tables in prose match the contract
pnpm ab-key:check               # Tool descriptions still name the A/B traffic key
pnpm surface:check              # Nothing internal reached a public file
pnpm registry:check             # server.json agrees with package.json and src/mcp/server-info.json
pnpm schemas:check              # tools/list matches the recorded snapshot (needs a build)
pnpm test:fact-key              # Fact key grammar
pnpm test:decimals              # Metric precision display
pnpm test:export-format         # Export byte fidelity
pnpm protocol:check             # README matches the revisions the server serves

Security

Report a vulnerability through GitHub's private reporting form. The policy, including what is in scope, is in SECURITY.md.

License

Apache-2.0